The present invention relates to brakes for motor vehicles, and more particularly to such brakes having a caliper member straddling an annular cylindrical braking member and mounted for pivotal and sliding movement on a fixed support.
U.S. Pat. No. 3,853,207 assigned to the assignees of the present application describes a brake for a motor vehicle of the type comprising a fixed support, an annular generally cylindrical rotary braking member, brake shoes disposed respectively inside and outside the braking member, a C-shaped caliper member which is in radial engagement with the brake shoes and the braking member, and control means for urging the first brake shoe into engagement with the braking member and at the same time against the other brake shoe to grip the braking member therebetween; the caliper member is slidably and pivotally mounted on the fixed support by means of a pivot pin which extends between two leg portions of the fixed support and traverses the caliper member.
Such sliding and pivotal mounting of the caliper member advantageously permits the caliper member to accommodate for possible conical deformations of the cylindrical braking member.
In the embodiment described in this patent, the pivot pin mounting the caliper member passes through a passageway therein substantially free of play. The passageway has a transverse cross section which, overall, is complementary to that of the pivot pin but, on the contrary, for the desired sliding movement, is received in generally radially elongated slots in the leg portions of the fixed support.
One of the problems to be overcome with such a brake design is to enable the leading leg portion of the fixed support relative to the direction of rotation of the braking member to participate in bearing the braking force. Indeed, since the brake shoes are usually bounded by the leg portions, during braking, owing to the tendency to be subjected to circumferential displacement due to them being applied against the braking member, they abut circumferentially against the lagging leg portion of the fixed support only.
In order that the lagging leg portion may partake in absorbing the braking force it has already been contemplated to fasten the leading and lagging leg portions of the fixed support together by a connecting bar. But in such known arrangements the connecting bar invariably increases the radial and/or axial dimensions of the brake which at least for certain uses may make it difficult to accommodate such a brake.